Support list_outputs and transfer_so commands in simplewallet RPC

[Ljzn]

Description

Currently, the list_outputs and transfer_so commands are only accessible via the wallet shell interface. It would be highly beneficial to expose these methods through the Wallet JSON RPC API as well.

Why is this needed?

• ​Interoperability: Enabling remote and programmatic usage via JSON RPC would allow easier integration with external tools, scripts, and applications.
• ​Automation: JSON RPC support is essential for automating wallet operations without manual shell interaction.
• Consistency: Providing feature parity between the shell and RPC interfaces improves usability and developer experience.

Proposed Solution

Add JSON RPC endpoints for:

1. list_outputs – to retrieve a list of wallet outputs (e.g., for tracking or auditing purposes).
2. transfer_so – to enable constructing and signing transactions with specified outputs programmatically.
   These should mirror the functionality already available in the shell.

Example Use Case

A third-party service or script could use the JSON RPC methods to:

• Monitor wallet outputs without manual intervention.
• Construct custom transactions safely and efficiently in an automated workflow.

Additional Context

This change would significantly enhance the flexibility of the wallet interface, especially for developers building on top of the node/wallet infrastructure.

Thank you for considering this feature request!